1. Field of the Invention
The present invention relates to an image processing apparatus and image processing method. More particularly, the invention relates to an image processing apparatus and image processing method which determine an attribute of color image data for each predetermined line.
2. Description of the Related Art
In known image forming apparatuses, various methods are employed in order to improve the recording speed. For example, in an image forming apparatus using an ink-jet method for recording, an apparatus for improving the recording speed has been proposed in, for example, Japanese Laid-Open Patent Application Publication No. 2004-034327 (Japanese Patent Application No. 2002-190546). In the apparatus, a black (Bk) print head is made longer than the other color print heads, and a determination is made on whether the document is a monochrome area or a color area for each line. For a group of lines in a monochrome area, printing is performed using the long, black print head. Even a color image is printed by widening the range that can be printed at a time without deteriorating the image quality.
However, in the image forming apparatus using the known ink-jet method described above, the luminance signal read by the reader is directly image processed. By the inconsistency of linearity which arises in the reader, a group of lines originally determined to be monochrome are sometimes determined to be color. In this case, the group of lines is printed by the color head. Thus, there is a problem in that it takes time to copy a color document mixed with black.
That is to say, in the proposed apparatus described above, when attributes are appropriately determined in the wide area of image data, there is a problem in that the structure of the apparatus is complicated, and an image cannot be formed with high image quality.